Godzilla Zenless Zerø

Zenless Zone Zero x Godzilla Crossover

Kai-Sei is a mysterious radiation energy source roaming in this world are a mysterious new breed of humans empowered by the radiation, some capable of superhuman abilities and others physically transformed into kaiju themselves. Kai-Sei is a portmanteau of Kaiju and "Sei", the old Japanese word for "essence" from the old civilization. In other words, it's Kaiju Essence

"They're not on our world, We're in Theirs."

Centuries of war have reduced the Earth to shambles, forcing what remains of humanity trying to survive in a broken post-apocalyptic city of New Eridu, where humanity survives by navigating dangerous dimensional anomalies called "Hollows" that spawn monstrous creatures called Ethereals as humanity continues its war against ethereal, but little did they know an ancient, species older than humanity well soon returns known as kaiju long-forgotten force of nature who hail from a time long before existence of mankind & Ethereals making them not only gigantic superspecies but the oldest species. Many of them are quite large, the largest. They are very rarely seen and prefer to remain in hibernation, however, they are quite powerful. In spite of the destruction they cause, they also possess abilities that restore the environment to a primitive state, such as radiation that triggers growth in plant life. begins to awaken. The Earth's original and rightful rulers, the Titans. And among these Titans, an old king rises to reclaim his throne.